He is estivating. Estivation is a response to what they perceive to be negative changes to their environment. Often, for cool weather amphibians, it's a sort of 'summer hibernation'. Unlike true hibernation, it does not harm the animal to gently bring him out of it. He is, after all, just trying to live through a hardship which you are now going to remove. Here's what you can try: First, even though a pacman doesn't move for days on end, they like to have the option. Put him in a ten gallon tank (or larger), with a large shallow water dish. Make sure the rest of the soil stays clean and damp, like a squeezed out sponge, deep enough to bury himself if he chooses. Next, frogs don't like light, and a pacman doesn't need or want plants. In a 12 inch square that he has to share with plants and a light, he's probably very uncomfortable as he gets larger. So, 10 gallon with moist, deep peat and a water dish. Now, you can bring him out of estivation by holding him over the sink and letting room-temp water slowly run over him. After a few minutes, very gently rub the cocoon away, especially from his eyes. It will be gooey. Next, put him in his water dish in his new tank. Whenever he gets out, try to feed him. If he doesn't eat, try again in a few days. Amphibians are tremendously sensitive to their environment; you're probably never going to get him on a schedule. Keep us posted!
Noelle